28.81% chance to completely avoid damage (through the attack missing, being dodged, or being parried)
All other possibilities are for the attack to be blocked. Blocked attacks cannot crit or be Crushing Blows. All damaging attacks will be Blocked ones as no other option exists within the parameters of the Combat Table.

The thing the chaps my hide.. is that standing in their skivvies, with a shield a Protection warrior has already pushed Crushing Blows off the table.
Acutally not so much Nibuca. Here’s two portions of the Paladin Tanking guide from WoWInsider:“Lots of people like to say Warriors are Crushing Immune but that is false. There seems to be a lot of anecdotal evidence that Crushing has been switched to a Proc Per Minute. Mobs have a 15% chance to crush, but most Warriors are saying that as soon as they lose shield block they get crush after crush (which supports PPM). There are no logs to back this up so it could be that humans like to apply patterns where there are none. Regardless – Warriors can be Crush immune for two attacks every 5 seconds under best conditions. That does not make them crush immune.”
And“I mentioned Warrior before because it seems that many Paladins say to themselves, “We don’t have the Shield Block ability so we can never be as good as Warriors” (and a lot of Warriors want them to believe that). But Warriors are not Crush Immune – this is even more true if Crushes are indeed PPM. The difference between a base 15% crush vs. a 15% PPM to crush is massive. That means as soon as you become un-immune you will get crushed with near 100% frequency until the PPM requirements are fulfilled.”
Reality: With the current mechanics of Shield block, through intelligent use of it, and keeping track of Crushing blows dealt so far, a smart Warrior can effectively use Shield Block to control damage dealt. A stupid Warrior who spams Shield Block every chance he can, and gets lucky during the first half of a minute, may very well find himself at the end of a minute totally destroyed as he gets Crushing Blow after Crushing Blow.
Again: They are not Crush Immune. That’s just a lie that some of them want us to believe so they can keep their current position of “top tank all the time”.

And honestly, while it’s cool for more parry, I’m leaning towards going 10/41/10, with the 10 points in the Ret tree being less mana spent on seals ability, Improved Judgements and Impoved SotC for better aggro generation. The additional 10 points in Holy goes for Divine Intellect for a little extra mana and spell crit (anyone who says Pally Tanks need no INT is delusional, we may not need a lot, but we need some), and the improved Improved Seal of Righteousness.